This invention generally relates to vascular catheters suitable for maintaining the patency of a blood vessel after a vascular procedure therein, such as angioplasty.
In typical percutaneous transluminal coronary angioplasty (PTCA) procedures, a guiding catheter having a preformed distal tip is percutaneously introduced into the cardiovascular system of a patient through the brachial or femoral arteries and advanced therein until the distal tip thereof is in the ostium of the desired coronary artery. A guidewire and a dilatation catheter having a balloon on the distal end thereof are introduced through the guiding catheter with the guidewire slidably disposed within an inner lumen of the dilatation catheter. The guidewire is first advanced out of the distal end of the guiding catheter into the patient's coronary vasculature until the distal end of the guidewire crosses the lesion to be dilated and then the dilatation catheter is advanced over the previously positioned guidewire until the dilatation balloon is properly located across the lesion. Once in position across the lesion, the flexible, relatively inelastic balloon of the dilatation catheter is inflated to a predetermined size (preferably the same as the inner diameter of the artery at that location) with radiopaque liquid at relatively high pressures (e.g., greater than about 4 atmospheres) to radially compress the atherosclerotic plaque of the lesion against the inside of the artery wall to thereby dilate the lumen of the artery. The balloon is then deflated so that the dilatation catheter can be removed and blood flow resumed through the dilated artery.
Further details of angioplasty procedures and the devices used in such procedures can be found in U. S. Pat. No. 4,323,071 (Simpson-Robert); U.S. Pat. No. 4,332,254 (Lindquist); U.S. Pat. No. 4,439,185 (Lundquist); U.S. Pat. No. 4,168,224 (Enzmann et al.); U.S. Pat. No. 4,516,972 (Samson); U.S. Pat. No. 4,582,181 (Samson); U.S. Pat. No. 4,538,622 (Samson et al.); U.S. Pat. No. 4,597,755 (Samson); U.S. Pat. No. 4,616,652 (Simpson); U.S. Pat. No. 4,748,982 (Horzewski et al.); U.S. Pat. No. 4,771,778 (Mar); and U.S. Pat. No. 4,793,350 (Mar et al.) which are hereby incorporated herein in their entirety.
Frequently, the stenotic plaque or intima of the blood vessel or both are dissected during the angioplasty procedure by the inflation of the balloon, so that upon the deflation of the balloon a section of the dissected lining, commonly termed a "flap," will collapse into the bloodstream, closing off blood flow through the vessel and thereby abruptly stopping or significantly reducing the passage of blood therethrough. In these instances, emergency bypass surgery is usually required to avoid a myocardial infarct distal to the blockage.
Conceivably, the dilatation catheter could be replaced with a perfusion type dilatation catheter such as described in U.S. Pat. No. 4,790,315 in order to hold the blood vessel open for extended periods. However, perfusion type dilatation catheters have relatively large profiles which can make advancement thereof through the blockage difficult and therefore immediate bypass surgery may be the only means of avoiding an infarct distal to the blockage or possibly even death. Additionally, the inflated balloon of these perfusion catheters can block off a branch artery, thus creating ischemic conditions in the side branch distal to the blockage.
Copending application Ser. No. 283,729 filed Dec. 13, 1988, describes an intravascular catheter having an expandable cage on the distal end thereof which is designed to hold a detached lining against an arterial wall for extended periods to facilitate the reattachment thereof. However, this vascular device does not have means to readily advance and withdraw the device over a guidewire.
What has been needed and heretofore unavailable is an easily advanceable and removable low-profile intravascular device which can hold a collapsed dissected lining or flap against the blood vessel wall for sufficient length of time to allow the natural adhesion of the flap to the blood vessel wall while simultaneously allowing for the perfusion of blood distal to the catheter without blocking a branch artery. The present invention satisfies this need.